Biomedical Engineering Reference
In-Depth Information
spermine) are volatile amines that are produced as a result of the break-
down of amino acids. Histamine has been identii ed as the causative agent
of the disease Scombrotoxicosis or scombroid poisoning, which can, in
severe cases, cause symptoms such as headache, nausea, vomiting, diar-
rhoea, itching, oral burning sensation, red rash and hypotension. Biogenic
amines may also be considered as carcinogens because of their ability to
react with nitrites to form potentially carcinogenic nitrosamines.
In 2010 Piermarini
et al.
[58] presented a simple and rapid method for
the analysis of biogenic amines in human saliva by using DaOx immo-
bilized on a PB-modii ed SPE. h e biosensor response was investigated
for dif erent amines such as putrescine, cadaverine, spermine, histamine,
etc
. h e results obtained during the evaluation of saliva showed that the
developed electrochemical biosensor can be considered a valid point-of-
care testing method for the determination of salivary polyamines, as well
as being suitable for biomedical studies.
12.4.1.7 CholineOxidase
Choline oxidase (ChlOx, EC 1.1.3.17) is an enzyme that catalyzes the oxi-
dation of choline to generate glycine betaine
via
betaine aldehyde with
H
2
O
2
generation. h e enzyme acts on the CH-OH groups of donor with O
2
as electron acceptor and FAD as cofactor. Choline and its metabolites are
needed for three main physiological purposes such as structural integrity
for cell membranes, cholinergic neurotransmission and a major source for
methyl groups via its metabolite, betaine. On the other hand, choline, as a
marker of cholinergic activity in brain tissue, is very important in biologi-
cal and clinical analysis, especially in the clinical detection of neurodegen-
erative disorders.
In 2006, Shi
et al.
[59] reported an amperometric choline biosensor
based on the immobilization of ChlOx in a layer-by-layer (LBL) multilayer
i lm on a PB-modii ed Pt electrode. h e authors suggested that the high
sensitivity and fast response time observed may be due to the ei cacy of
the enzyme immobilization and to the ultrathin nature of the LBL i lm, in
which mass-transport problems were minimized. h e analytical values of
choline in serum samples obtained by this choline biosensor agreed satis-
factorily with those by a spectrophotometric method. Finally, the choline
biosensor retained ~86% of its initial current response to choline at er ca.
2 months.
In 2012, Zhang
et al.
[60] developed an electrochemical approach for
the detection of choline based on PB-modii ed iron phosphate nanostruc-
tures (PB-FePO
4
). h ese nanostructures showed a good catalysis toward
